DE4440393C2 - Device for coating rotationally symmetrical moldings - Google Patents

Abstract

A device and a roller are disclosed for coating the outer surface of rotationally symmetrical moulded bodies, in particular bottles. The device has means for transporting and holding the revolving moulded bodies (3) that are to be coated, a coating mass casting head (6) and at least one rotary roller (4) that can be pressed on and lifted again off the moulded body (3). When the roller (4) is pressed against the moulded body (3), its axis of rotation is at least substantially parallel to the axis of rotation of the moulded body (3). The roller (4) spreads the coating mass on the outer surface of the moulded body (3) and has an outer contour that matches the outer contour of the shaped body (3). The coating mass is thus uniformly spread on the outer surface of the moulded body (3) before hardening.

Description

The invention relates to a device for coating the Outer surface of rotationally symmetrical moldings, esp special bottles, according to the preamble of claim 1.

There are already various devices for coating Bottles with flowable material, e.g. plastic, known. In this regard, is representative of DE 28 30 316 A1 and the publications cited therein. With the it is known from DE 28 30 316 A1 injection or pouring head be possible to have an exact, uniform coating of the fla guarantee.

To apply liquids to bottles are already spe machines with their own drive and a fla transport stars moving on a circular arc knows. Such a device is for example in the EP 0 452 943 A. In this known device the bottles in the transport star by rolling on a fixed friction segment set in self-rotation and thereby charged with the liquid. This liquid becomes ins special applied for the purpose of reusable bottles after several rounds of chafing and son chipping and scratches on the cylindrical bottle to cover the fuselage and the bottles are in mint condition to give the appearance.

Devices are also known, for example from the US 4586458, in which the liquid from a rela tiv to an application element moving spray nozzle by means of Zwi casters is transferred.

There is now a need in the beverage industry after, the hollow body required for packaging, esp special glass bottles in disposable and reusable areas, always lighter to save material and transportation costs.  

However, the walls of such bottles cannot be arbitrary be trained thinly as this involves significant risks brings. So are off with drinks containing CO₂, for example filled bottles through the filling media a permanent internal pressure exposed. Now becomes the surface of a thin-walled bottle damaged, then such pressurized bottles easily burst. This can lead to obvious product lead claims.

In addition, the outer surface of reusable bottles when Cleaning and filling normally damaged and scratched becomes. Since the material glass has the property that its sta bility primarily influenced by the condition of the surface a pressurized glass bottle can already be used only slight damage to the surface, etc.

It is already known to bottle with an outer coating provided that the surface of the bottle from damage rend the filling company etc. protects and even a zer splintered bottle in its shape "can hold together". As a Such coating material can be from Hüls AG product sold under the name "Vesticoat" set, which is described in DE 29 38 309 A1 and EP 0 025 932 A and DE 29 38 229 A1 or EP 0 025 994 A. Through use such materials, it is possible to have thin walls and thus to use lighter bottles that are even safer than the previously known, uncoated glass bottles.

These known, flowable coating materials are made of Environmental reasons solvent-free. This has the disadvantage that these coating materials are relatively highly viscous and not simply by spraying, dipping or pouring can be applied. This highly viscous coating machine materials are therefore currently strand-shaped by a casting or spray head on the bottle to be coated itself brings and then by blowing or by downstream Roll on the outer surface of the bottle to be coated distributed or equalized. In this context it is also known to apply the plastic strands on a roll and by means of this on the outer surface of the to be coated Transfer bottle. With this known technique is thus  the bottle rotatably held on her head and on her bottom turned; the said roll or Roller placed in contact with the bottle for a certain time long held in contact so that the coating material on the bottle surface is distributed. These previously used Rollers had a purely cylindrical shape. Because of that the coating material was not uniform on the top distributed over the surface of the bottle. There were therefore failures and Defective coatings. The coated bottles also fulfilled often not the quality criteria placed on them.

The object of the invention is therefore a device to provide with the highly viscous sol solvent-free coating materials reliable, the same can be applied moderately and reproducibly to moldings nen.

This problem is solved by the teaching of claim 1.

The device according to the invention has as well as that previously known devices a device for transporting and rotatable holders of the moldings to be coated. This before direction is called the transport device below. Which he device according to the invention is also with an infusion head for the coating material and with at least one rotatable press the molded body to be coated and lift it off again equipped roller. The axis of rotation of the roller in pressed state is at least substantially parallel to the Axis of rotation of the molded body to be coated and serves to distribute the coating compound on the outer surface surface of the molded body. This roller is after distribution of the Be Layered mass moved away from the molded body. The one on the Shaped coating composition is then per se known way hardened so that there is a protective outside layer or coating forms.

The highly viscous solvent-free Be Layer systems or paint systems are in particular especially around those with a viscosity of 40,000 mps at approx.  10 ° C up to 1,000 mps at approx. 100 ° C, especially 30,000 mps at 20 ° C to 5,000 mps at 70 ° C.

The expression "rotationally symmetrical" used here is not to understand in the strictly mathematical sense. It can be invented According to the invention, moldings coated by the Ro tation symmetry deviate slightly.

The inventive essence of the present invention now exists in that the roller for distributing the coating material a complementarily shaped to the outer contour of the molded body Has outer contour. In other words, the profile of the roller represents the negative profile of the molded body to be coated. One can also say that in the area, in the molded body and Roller come into contact, the lateral profile line of the one Level projected molded body with the side profile line the roller, which is also projected onto a plane, roughly together falls. This criterion can also be met if shape body and roller are dimensioned differently in this In this case, the roller and molded body can move at different speeds rotate. According to a preferred embodiment, have bottle and molded articles, however, have comparable or similar dimensions. More specifically, this means that the sum of the radius of the Roller and the radius of the molded body at any point about the same value along the longitudinal or rotational axis results in approximately the distance between the two axes of rotation in demje Nige condition corresponds, in the molded body and roller together who are pressed. One could also say that the roller is the ro tation-symmetrical negative form of the molded body to be coated pers or that the roller, based on the axis of rotation, to coat the rotationally symmetrical complementary form of the represents the shaped body.

Because of the shape of the roller used in the invention, it is possible, highly viscous coating materials with high produc speeds evenly on the glass to be coated distribute the hollow body so that after hardening a homogeneous, evenly distributed coating is obtained. The other applied high-viscosity coating materials expediently at an operating temperature of  30-100 ° C, especially at 40-60 ° C processed or on this Temperature warmed.

According to a further preferred embodiment, the up Casting head arranged in the device according to the invention net that the coating material first applied to the roller brings and then either staggered or by means of this roller is simultaneously transferred to the molded body. As an infusion head or application device can all known, for facilities used, for example Gießlei most, nozzles etc. are used. More appropriate however, the coating material is on the roller brought as long as the roller is not yet in contact with the coating molded body is.

In addition, the device according to the invention is more expedient as a known per se metering device. With this Dosing device can be a defi nated amount of coating material from a corresponding Casting bar over individual, combined nozzles on un Different areas of the roller are applied so that the most even distribution possible. This Thursday Siervorrichtung can also be designed and controlled in this way be that different amounts of coating material applied simultaneously to different areas of the roller will.

In the device according to the invention is at least either the molded body or the roller is positively rotated. If the molding by forcibly rotated, then the roller is in contact with the molding pers forced in the opposite direction. same for vice versa if the roller is positively turned. Preferably molded body and roller are rotated in opposite directions, esp especially with the same speed of rotation. Will that Coating material applied to the roller first, then roller and molded article to be coated as long as in Kon kept clock that the coating material used in sufficient or complete transfer.

According to a further preferred embodiment, the Roll a non-elastic core and an outside on it  brought elastic transmission material. The core can be a cylinder; in this case, the transmission material for the outer contour or for the outer shape of the roller " literal ". Therefore, the thickness of the transmission measure also changes terials according to the change in the shape of the be layered shaped body along the longitudinal axis.

According to a further preferred embodiment, the elastic transmission material along the entire length an equal layer thickness. In this case, the shape of the Core approximately the complementary form of the form to be coated body.

In both of the last described embodiments, the Core on its outer surface several radially circumferential nu possess ten, in the radially inwardly projecting beads of Intervene transmission material, so that an axial displacement transmission material with respect to the core is prevented.

Of course, it is also possible for the core to be radially outside has running beads, which in rotating, in the transfer engaging recessed grooves. The core owns expediently a central continuous to the axis of rotation kon central bore for receiving a bearing shaft etc.

The transfer material can be open-pored and made of moss rubber, foamed plastics or fibrous natural products, for example lambskin. The transmission material can also be closed-pore and made of foam rubber types and foamed plastics, especially EPDM and Po lyurethane plastics. The composition of the Transfer material and of course the core is purpose to be chosen moderately in such a way that it matches the coating dimensions is compatible with materials, does not swell and also chemically not is attacked. For example, tolerance should to coating materials based on Po given lyurethane, acrylate, epoxy and synthetic resin formulations his. In addition, the transmission material mechanical bean Withstand spells for as long as possible.  

The rotationally symmetrical core of the roller can be made of wood, art substances and metals, especially aluminum or steel quality.

This is because the roller consists of a core and an over is built up, the transmission material according to defined usage or wear criteria changed and renewed, so that the requirements of the Uniformity of the distribution of the coating material be filled.

The transmission material expediently has a thickness from 1 to 100 mm, especially 30 mm. Especially if the transmission material is the same over the entire length has moderate layer thickness, is as uniform as possible Contact pressure and thus the best possible distribution of the Given coating material.

As a transport device of the device according to the invention NEN all known transport devices application fin the. However, the transport device is preferably used for simultaneous transport of several be approximately even spaced moldings. With such a transport direction can be, for example, a transport star or a similar device. Preferably, the Transport device, however, is a common transport chain, in of the moldings to be coated lying horizontally and are rotatably supported at the same time spaced.

The device according to the invention preferably has several Rollers for coating one of the number of rollers at the same time corresponding number of moldings. The distance of the whale zen from each other corresponds approximately to the distance of the shape body from each other in the transport device. The reels are preferably held in a lifting carriage, the out Starting from a starting position in the direction of the Trans port device is moved that the rollers in about the same time be pressed against the molded body to be coated. In this pressed state is then the lifting carriage with the same speed as the transport device as well moved parallel to this transport device so that the whale  zen pressed against the molded body. After a predetermined distance or after a predetermined time the lifting slide with the rollers is lifted off the molded bodies and returns to its original position.

This lifting carriage is equipped with at least one infusion head for example a watering bar. It's just an up casting head available, then this must be moved back and forth that each roller has enough of one during a cycle Appropriate amount of coating is provided. The coating quantity is preferably on the rollers in the time interval vall transfer in which the roller is not in contact with the Shaped body.

However, the lifting carriage is preferably one of the number of Rollers corresponding number of infusion heads equipped. These in this case are stationary with respect to the lifting carriage orderly. In other words, each roller is a separate winder assigned casting head.

According to a further preferred embodiment, the whales zen rotatably supported on a continuous endless chain. These Endless chain is guided in such a way that several rollers at the same time held in contact with the moldings assigned to them and with the speed of the transport device in parallel be moved. This endless chain becomes something like the chain of a caterpillar tractor.

It was explained above that the moldings to be coated or Bottles both on the head and on the bottom in the transport are rotatably supported. This double-sided bracket is primarily due to the fact that when pressing the roller on due to the highly viscous coating material a not to be ver careless pressure must be exerted, of course, by to hold the bottle holder.

In an effort to save additional weight, also may be required to coat the bottom of a bottle. In this case, the storage of the bottle is in the transport device only possible on the head, for example with the help of a expanding mandrel engaging in the bottle mouth. Would one  roller described here is attached to a bottle so stored be pressed, then there is a great risk that the Bottle neck breaks off.

In order to counter this danger, the front according to the invention direction according to a preferred embodiment with at least a back-up roller equipped to distribute the roller Coating composition is arranged opposite and at least least in the area where the roller against the be layered bottle is pressed, also by the counter overlying side pressed against the bottle to be coated is so that only ge on the holder of the bottle on the mouthpiece ring loads occur. This back-up roller must, of course the same speed as the transport device and the roller used to distribute the coating compound in parallel lel to the bottle to be coated and moved.

The roller is used to distribute the coating compound from above against the bottle to be coated, then Of course, the above-mentioned back-up roller is quasi as Wi the bearing pressed against the bottle to be coated. Naturally the back-up roller must also be rotatably mounted.

As a back-up roller you can use a conventional cylindrical roller bring turn. However, this suitably has Back-up roller the same shape as the distribution roller the coating mass.

According to a further preferred embodiment, several in particular two support rollers lying next to each other are provided, the lateral distance between the two support rollers is such is chosen that they are a kind of bed or camp for the Form the coating bottle. The lateral distance from each other other facing outer surface of the support rollers is thus less than the diameter of the bottle to be coated. With in other words, one connects, in the direction of the axes of rotation hen, the axis of rotation of the roller to distribute the coating dimensions with the axis of rotation of the bottle and this in turn with the two axes of rotation of the support rollers, then there is a Y, where with this Y preferably "upside down". Also in this  Fall can support rollers with respect to their outer contour be shaped like the roller for distributing the coating mass.

The invention is described below based on the preferred embodiment approximately figures illustrated. Of the Figures show:

Fig. 1-3 each have a complementary bottle to be coated and the dazuge hearing roll form,

Fig. 4 is a diagrammatic functional representation of a OF INVENTION to the invention apparatus having lifting slides with a plurality of rollers and Aufgußköpfen,

Fig. 5 is a representation corresponding to FIG. 4 but with only one infusion head

Fig. 6 is a Fig. 4 corresponding representation, wherein each but are supporting the rollers ge on a revolving endless chain,

Fig. 7 is a representation corresponding to Fig. 6, but there are only two infusion heads and

Fig. 8 is a perspective view of a molded body to be coated with an associated roller and associated infusion head.

In FIG. 4 a transport device 2, here a port chain Trans, of the device according to the invention is shown in highly simplified form sketched. Such a transport chain 2 is known. The moldings to be coated, here bottles 3 , are held horizontally and arranged at approximately the same distance from each other par allel. The bottles are held on the head and on the bottom, because in these areas the bottles have a sufficient wall thickness so that these areas do not have to be coated. The bottles 3 can be rotated about their longitudinal axis.

The lifting carriage 5 shown in FIG. 4 is equipped with four rollers 4 , which are described in more detail below. These rollers 4 are at a distance from one another which corresponds to the distance between the bottles 3 . Each of the rollers 4 is equipped with a separate infusion head 6 through which the coating material is applied in metered quantities to the associated roller 4 .

The lifting carriage 5 can carry out a translatory back and forth movement as well as a lifting movement according to the arrows shown in FIG. 4. To carry out the coating process, the lifting carriage is brought from a starting position, not shown, in which rollers 4 and bottles 3 have no contact with one another, into the position shown in FIG. 4. From there, the lifting carriage 5 is moved parallel to the trans port chain 2 and at the same speed in the direction of the arrow pointing to the right. The coating material applied to the rollers 4 is transferred to the bottles 4 and distributed on the outer surface thereof. The bottles 3 and the rollers 4 are both positively rotated in opposite directions.

After a predetermined time or after a predetermined distance, the lifting carriage is raised and returns to its starting position, not shown. During this movement sequence, the coating material is applied in metered quantities to the rollers 4 which are still rotated.

The moldings and rollers used can have the shapes shown in FIGS. 1 to 3. As can be seen from these figures, the outer contour 8 of the roller 4 has a shape that is complementary to the outer contour 9 of the bottle 3 . The sum of the radius a (see FIG. 1) of the Fla cal 3 and the radius b of the roller 4 is equal to the distance between the longitudinal axis of the bottle 10 and the longitudinal axis 11 of the roller 4 in the pressed state. In other words, the sum of a and b corresponds to the sum of x and y of FIG. 1. However, it is assumed that the transfer material 12 of the roller 4 is not compressed when pressed on. In fact, this is the case. The above calculations thus relate to the state in which the roller 4 is pressed against the bottle 3 without compression of the transmission material 12 . In the actual coating process, however, the transfer material 12 is compressed slightly.

The roller 4 and the bottle 3 are rotatably supported and stored on their two foreheads. The facilities required for this are known and also not shown.

The roller 4 has a hollow cylindrical core 13 which is surrounded on the outside with the transfer material 12 . The core 13 be sits on its outer circumferential surface a plurality of radially circumferential grooves 14 , engage in the radially inwardly projecting beads 15 of the transmission material 12 .

In the embodiment shown in FIG. 2, the core 13 is quasi the cause of the negative shape of the bottle 3 . This core 13 carries on its outer surface the transmission material 12 , which has approximately the same layer thickness along the longitudinal axis 11 . Due to this uniform layer thickness it is ensured that the contact pressure and thus also the distribution of the coating material on the entire outer surface of the bottle 3 is approximately the same.

The diagram shown in Fig. 5 corresponds wesentli chen the illustration of FIG. 4. The difference is that only a Aufgußkopf 6 is in the embodiment of Fig. 5 exists, the back and forth so that the coating material is applied to all four rollers 4 . The infusion head 6 can thus be moved back and forth with respect to the lifting carriage, not shown.

The illustration shown in FIG. 6 also corresponds approximately to the illustration shown in FIG. 4. However, the rollers 4 are held on an endless chain 16 running like a caterpillar tractor. The rollers 4 are guided from a starting position A to the transport chain 2 and brought into contact with a bottle 3 . From this position B, the roller 4 is guided parallel to the transport chain 2 with the roller 4 and bottle 3 rotating in opposite directions to a point C. There the roller 4 is lifted from the bottle 3 and led to point D. There the coating material is applied to the roller 4 by means of the infusion head 6 .

The lifting carriage 5 has four infusion heads 6 and can be moved back and forth according to the upper arrow x.

In this embodiment too, the infusion heads 6 are moved horizontally back and forth with the associated carriage. However, lifting and lowering is not necessary.

The embodiment shown in FIG. 7 corresponds approximately to the embodiment shown in FIG. 6. The difference is that the carriage 5 sits only two infusion heads, which are moved back and forth according to the arrow x.

The speed of rotation of the bottle and roller can in practice rigen in all embodiments, in particular 1 U / min. up to 300 RPM be. This speed of rotation is useful moderately adjustable.

In Fig. 8, a typical infusion head 6 with a pouring ledge 18 is shown. From this pouring strip 18 , the coating material required is transferred to the roller 4 in metered amounts. The design of the infusion head is usual.

The roller 4 has the core 13 already described above with the elastic transmission material 12 and a central through bore 17 which is concentric with the axis of rotation. This roller 4 is pressed against the bottle 3 and thereby transfers the coating material to the bottle 3 and distributes it on the outer surface.

Due to the fact that each bottle to be coated or each molded article to be coated is assigned a "separate" roller, the frequently occurring circumstance can also be taken into account that a space for a molded article 3 is often not in the transport device 2 coating molded body 3 is occupied.

Therefore, the device according to the invention can be equipped with a detection device, not shown, which determines whether such a molded article is actually present at a place for a molded article in the trans port device 2 or not. If there is no molded article to be coated, this information is communicated to a control and regulating device for metering the amount of coating material. This control device then ensures that no coating material is transferred to the roller 4 if the shaped body to be coated or the bottle 3 to be coated is not present in the transport device 2 . In this way it is ensured that the intended amount of coating material is applied to the respective roller for each bottle and is then transferred from this to the bottle 3 to be coated. In other words, it is avoided that the coating material applied to the respective roller in one working cycle is not transferred to the bottle 3 but remains on the roller 4 , to which the same coating amount is then applied again in the next working cycle, so that then double the amount of coating is transferred to the next bottle to be coated. In this way, a reproducible, uniform coating that meets the requirements is achieved.

Claims (11)

1. Device for coating the outer surface of rotationally symmetrical moldings, in particular bottles, with a device ( 2 ) for transporting and rotating holders of the moldings to be coated (transport device), with a pouring head ( 6 ) for the coating material and with at least one rotatable, on the molded body ( 3 ) pressable and removable roller ( 4 ), the axis of rotation ( 11 ) in the pressed state is arranged at least substantially parallel to the axis of rotation ( 10 ) of the molded body ( 3 ) for distributing the coating material on the outer surface of the molded body ( 3 ), characterized in that the roller ( 4 ) has an outer contour ( 8 ) complementarily shaped to the outer contour ( 9 ) of the molded body ( 3 ). 2. Device according to claim 1, characterized in that the sum of the radii of roller ( 4 ) and molded body ( 3 ) at each point along the longitudinal or rotational axes ( 10 ; 11 ) approximately the distance between the two axes of rotation ( 10 ; 11 ) corresponds to the pressed state. 3. Apparatus according to claim 1 or 2, characterized in that the coating material is first applied to the roller ( 4 ) and then transferred to the shaped body ( 3 ) by means of the latter. 4. Device according to one of the preceding claims, characterized in that the shaped body ( 3 ) and the roller ( 4 ) are positively rotated in opposite directions, in particular with the same rotation speed. 5. Device according to one of the preceding claims, characterized in that the roller ( 4 ) has a non-elastic core ( 13 ) and an elastic transmission material ( 12 ) applied to the outside, in particular with a uniform layer thickness. 6. Device according to one of the preceding claims, characterized in that with the transport device ( 2 ) a plurality of approximately equally spaced molded bodies ( 3 ) are continuously transported and that a plurality of rollers ( 4 ) are vorgese hen, the distance between the rollers ( 4 ) from each other speaks approximately the distance between the shaped body ( 3 ) ent. 7. The device according to claim 6, characterized in that all the rollers ( 4 ) are held in a lifting carriage ( 5 ) which, starting from an initial position, is moved in the direction of the transport device ( 2 ) such that the rollers ( 4 ) approximately are pressed simultaneously to the them depending weils associated mold body (3), which then with the speed of the transport device (2) and is moved parallel to the device from the transport (2) is moved away and returns to its initial position. 8. The device according to claim 7, characterized in that each of the rollers ( 4 ) of the lifting carriage ( 5 ) is equipped with a separate infusion head ( 6 ). 9. The device according to claim 7, characterized in that the lifting carriage ( 5 ) is equipped with only one infusion head ( 6 ) which can be moved back and forth in such a way that the required coating composition is applied to each roller ( 4 ). 10. The device according to claim 6, characterized in that the rollers ( 4 ) on a circulating endless chain ( 16 ) are held, which is guided such that some of the rollers ( 4 ) at the same time on the respective molded body ( 3 ) in plant held and moved at the speed of the transport device ( 2 ) parallel to it. 11. Device according to one of the preceding claims, characterized in that the shaped body ( 3 ) in the transport device ( 2 ) are held horizontally parallel to each other and the roller (s) ( 4 ) from above onto the shaped body ( 3 ) is pressed ( become).